A Potential Animal Model of Maladaptive Palatable Food Consumption Followed by Delayed Discomfort

Abstract

Introduction: Binging is the consumption of larger amounts of food in a briefer period of time than would normally be consumed under similar circumstances. Binging requires palatable food (PF) to trigger abnormal eating, probably reflecting gene × environment interactions. In this study we examined the impact of trait binge eating (BE) and its compulsive nature on the conflict between hedonic eating of PF and anticipation of a delayed aversive effect. We used female rats as an animal model similar to other models of BE. A novel aspect of this model in this paper is the use of a delayed internal aversive effect produced by lactose ingestion. Establishing this model will allow us to better understand the nature of the conflict between immediate reward and its delayed aversive implications. We hypothesized that BE prone (BEP) rats will demonstrate maladaptive decision making, presenting higher motivation toward PF even when this is associated with delayed discomfort.Method: (Phase 1) 52 female adult Wistar rats were divided to two eating profiles: resistant and prone binge eaters (BER/BEP) based on intake of liquid PF (Ensure). Next, all subjects underwent a Lactose Conditioning Protocol (LCP) that included 4 h tests, one baseline and 3 conditioning days (Phase 2), in which solid PF (Oreo cookies) was paired with glucose (control-no internal aversive effect) or lactose, dissolved in liquid PF. Index for PF motivation was PF consumption during the 4 h LCP. To test for memory of lactose conditioning, we performed another LCP with glucose only (anticipation, but no actual lactose-induced discomfort), a week after the last conditioning session.Results: Lactose conditioned BEP showed higher motivation toward PF compared to lactose conditioned BER faced with delayed aversive effects. Only lactose conditioned BER rats devaluated the PF over LCP days, indicating an association between PF and abdominal discomfort. In addition, only lactose conditioned BER presented an adaptive dynamic behavior, by varying PF intake according to consequences. Furthermore, solid PF consumption was predicted by binge size of liquid PF, only for lactose conditioned rats.Conclusions: We established an animal model for a common eating conflict in humans using delayed internal aversive unconditional stimuli.

Breaking It Down: Investigation of Binge Eating Components in Animal Models to Enhance Translation

“…Indeed, complex PF developed for animals (e.g., pelleted formulas) has been used to successfully elicit binge-like eating after intermittent exposures ranging from 30 min to 2 h (70, 71, 102). Findings have been replicated using a variety of complex PFs including Nutella combined with food pellets and water (55-59, 77), Reeses Peanut Butter Drops and Nestle Chocolate Drops (103), Ensure drinks (104,105), and sweetened condensed milk (106). Rates of BE-proneness are similar across studies using complex PF types high in both sweetness and fat such as Oreo cookies (45,54) and vanilla frosting (47,49,51,52).…”

“…Using a consistency of consumption threshold, animals that consumed high amounts of PF and consistently maintained intake of PF within 10-15% across consecutive days were identified as being in a chronic binge eating state (69)(70)(71). Groupings have also been made using statistical cutoffs (e.g., median split, tertiles) based on consistency of PF intake during a study period to identify extreme groups of BE-prone and BE-resistant animals (45,48,54,65,72,73,89,90,105). This allows for comparison between extreme BE and non-BE groups for analysis, which is translationally relevant to work comparing BE and non-BE human populations within a study (112,113).…”

“…Specifically, animals with a history of intermittent access to PF demonstrate more willingness to experience foot shock (84,86), endure repeated foot shocks increasing in intensity (54), and spend more time in the light side of a lightdark chamber where PF was presented compared to animals without a history of intermittent PF access (73,89). BE-prone animals were also more likely to continue daily consumption of PF combined with lactose (which leads to physical discomfort) compared to BE-resistant animals that reduced PF + lactose intake over time (105). These findings suggest that animals with binge-like eating may have a higher likelihood of compulsive behavior, suggesting potential relevance to loss of control in BE.…”

“…Here, animals are offered equal access to PF, similar to human exposure to PF. Groups are then identified based on the PF consumption during the paradigm (highest/consistent PF intake are BE, lowest/ consistent consumption of PF are non-BE/control group) (45,48,52,72,73,89,90,105,134), resulting in comparison of extreme groups of BE and non-BE animals.…”

Uma proposta interventiva à compulsão alimentar de indivíduos submetidos à cirurgia bariátrica

“…Os episódios de compulsão alimentar estão presentes na classificação dos trans tornos alimentares (TA) do Manual diagnóstico e estatístico de transtornos mentais (DSMV), organizado pela American Psychiatric Association (2013). Tais episódios são definidos pela ingestão de alimentos, em um curto período de tempo, em quantidade maior do que a maioria das pessoas consumiria sob circunstâncias similares (Moshe, Bekker, & Weller, 2017). Os episódios são marcados pela sensação de falta de controle e pelo sentimento de culpa ou vergonha, usualmente descritos por aqueles cujo com portamento alimentar se define como compulsivo.…”